C2 prosthesis: anterior upper cervical fixation device to reconstruct the second cervical vertebra

Implantation of C2 prosthesis with dorsal fusion C0-C4 due to pathologic C2 fracture. Case report and literature review

INTRODUCTION

Pathological destruction of the axis vertebra leads to a highly unstable condition in an upper cervical spine. As surgical resection and anatomical reconstruction of the second cervical vertebrae represents a life threatening procedure, less radical approaches are preferred and only few cases of C2 prosthesis are described in literature.

CASE DESCRIPTION

The focus of this case report is a 21-year-old man with a pathological fracture of C2 managed primarily surgically with the C1-C3 dorsal fusion. Due to the progression of giant cell tumor and destruction of the axis vertebra, C2 prosthesis through anterior approach and dorsal occipito-cervical fusion C0-C4 were performed. Postoperative infection was managed surgically with a 2-staged dorsal debridement, ostheosynthesis material change and autologous bone graft. After a 4 week-intravenous therapy with the ceftriaxone in combination with the amoxicillin/clavulanate, followed by 12 week per oral therapy with amoxicillin/clavulanate in combination with ciprofloxacin, the complete recovery of the infection was achieved. Radiotherapy was initiated 2 months after the last revision surgery and the patient showed a good clinical outcome with stable construct at a 1 year follow-up. A review of literature of all reported C2 prosthesis cases was performed CONCLUSION: C2 prosthesis allows a more radical resection in pathological processes involving the axis vertebra. Combined with the posterior fusion, immediate stability is achieved. Anterior surgical approach is through a highly unsterile oral environment which presents a high-risk of postoperative infection.

Technical aspects of total spondylectomy of C2

BACKGROUND

Tumorous involvement of the second cervical vertebra is an infrequent, but severe disease. Primary tumors and solitary metastases can be addressed by a radical procedure, a complete removal of the whole compartment. The second cervical vertebra has a highly complex anatomy, and its operation requires considerable surgical skills. The aim of this retrospective study is to present technical aspects of complete resection of C2 for tumor indications, clinical and radiological evaluation of our group of patients and comparison of results of recent reports on surgery in this region in the literature.

METHODS

Between 2006 and 2019 we performed 10 total resections of C2 for primary bone tumor or solitary metastasis at our department. Operation was indicated for chordoma in 4 cases and for other diagnoses (plasmacytoma, EWSA, metastases of papillary thyroid carcinoma, medullary thyroid carcinoma, lung carcinoma and sinonasal carcinoma) in one case each. The operative procedure was in all cases performed in two steps. It always started with the posterior approach. The anterior procedure was scheduled according to the patient's condition after an average interval of 16.9 days (range 7-21).

RESULTS

A stable upper cervical spine was achieved in all patients. A solid bone fusion over the whole instrumentation was present in all living patients and they returned to their preoperative activity level. By the final follow-up 6 patients died: one patient died on the 5th postop day because of diffuse uncontrollable bleeding from surgical wound, three patients died of generalization of the underlying disease and two patients due to complications associated with local recurrence of the disease. In addition to regular follow-ups, the surviving patients (N.=4) were also examined upon completion of the study, i.e., on average 91 months (range 17-179 months) postoperatively. With exclusion of an early deceased patient, the average follow-up period of deceased patients was 34.6 months (range 9-55) (N.=5). The average follow-up of the whole group of patients was 59,7 months (N.=9).

CONCLUSIONS

Total spondylectomy of C2 is an exceptional surgical procedure associated with risk of serious complications but offers chance for a complete recovery of the patient. Defining indications accurately, especially in solitary metastases, is very difficult even with current level of imaging and other testing. The quality of life of long-term surviving patients in our study was not significantly impacted.

Novelties for increased safety in cranio-vertebral surgery: a review

The cranio-vertebral junction (CVJ) was formerly considered a surgical "no man's land" due to its complex anatomical and biomechanical features. Surgical approaches and hardware instrumentation have had to be tailored in order to achieve successful outcomes. Nowadays, thanks to the ongoing development of new technologies and surgical techniques, CVJ surgery has come to be widely performed in many spine centers. Accordingly, there is a drive to explore novel solutions and technological nuances that make CVJ surgery safer, faster, and more precise. Improved outcome in CVJ surgery has been achieved thanks to increased safety allowing for reduction in complication rates. The Authors present the latest technological advancements in CVJ surgery in terms of imaging, biomaterials, navigation, robotics, customized implants, 3D-printed technology, video-assisted approaches and neuromonitoring.

Reconstruction after resection of C2 vertebral tumors: A comparative study of 3D-printed vertebral body versus titanium mesh

Background

Surgical resection of C2 vertebral tumors is challenging owing to the complex anatomy of C2 vertebrae and the challenges to surgical exposure. Various surgical approaches are available, but some are associated with excessively high risks of complications. An additional challenge is reconstruction of the upper cervical spine following surgery. In the last decade, additive-manufacturing personalized artificial vertebral bodies (AVBs) have been introduced for the repair of large, irregular bony defects; however, their use and efficacy in upper cervical surgery have not been well addressed. Therefore, in this study, we compared instrumented fixation status between patients who underwent conventional titanium mesh reconstruction and those who underwent the same resection but with personalized AVBs.

Methods

We performed a retrospective comparative study and recruited a single-institution cohort of patients with C2 vertebral tumors. Clinical data and imaging findings were reviewed. Through data processing and comparative analysis, we described and discussed the feasibility and safety of surgical resection and the outcomes of hardware implants. The primary outcome of this study was instrumented fixation status.

Results

The 31 recruited patients were divided into two groups. There were 13 patients in group A who underwent conventional titanium mesh reconstruction and 18 group B patients who underwent personalized AVBs. All patients underwent staged posterior and anterior surgical procedures. In the cohort, 9.7% achieved total en bloc resection of the tumor, while gross total resection was achieved in the remaining 90.3%. The perioperative complication and mortality rates were 45.2% and 6.5%, respectively. The occurrence of perioperative complications was related to the choice of anterior approach (p < 0.05). Group A had a higher complication rate than group B (p < 0.05). Four patients (4/13, 30.8%) developed hardware problems during the follow-up period; however, this rate was marginally higher than that of group B (1/18, 5.6%).

Conclusions

Total resection of C2 vertebral tumors was associated with a high risk of perioperative complications. The staged posterior and retropharyngeal approaches are better surgical strategies for C2 tumors. Personalized AVBs can provide a reliable reconstruction outcome, yet minor pitfalls remain that call for further modification.

Reconstruction of the cervical lateral mass using 3D-printed prostheses

Objective

This study aimed to investigate the outcome of using 3-dimensional (3D)-printed prostheses to reconstruct a cervical lateral mass to maintain cervical stability.

Methods

We retrospectively analyzed data of 7 patients who underwent cervical lateral mass reconstruction using a 3D-printed prosthesis, comprising axial and subaxial lateral mass reconstruction in 2 and 5 patients, respectively. Bilateral mass was reconstructed in 1 patient and unilateral mass in the remaining 6 patients.

Results

Using a 3D-printed lateral mass prosthesis, internal fixation was stable for all 7 patients postoperatively. No implant-related complications such as prosthesis loosening, displacement, and compression were observed at the last follow-up.

Conclusion

Reconstruction of the lateral mass structure is beneficial in restoring load transfer in the cervical spine under physiological conditions. A 3D-printed prosthesis can be considered a good option for reconstruction of the lateral mass as fusion was achieved, with no subsequent complications observed.

Revision surgery for incomplete resection or recurrence of cervical spine chordoma: a consecutive case series of 24 patients

PURPOSE

Chordomas are rare tumors with an annual incidence of approximately one per million. Chordomas rarely metastasize but show a high local recurrence rate. Therefore, these patients present a major clinical challenge, and there is a paucity of the literature regarding the outcome after revision surgery of cervical spine chordomas. Available studies suggest a significantly worse outcome in revision scenarios. The purpose of this study is to analyze the survival rate, and complications of patients that underwent revision surgery for local recurrence or incomplete resection of chordoma at the craniocervical junction or at the cervical spine.

METHODS

24 consecutive patients that underwent revision surgery for cervical spine chordoma remnants or recurrence at a single center were reviewed retrospectively. We analyzed patient-specific surgical treatment strategies, complications, and outcome. Kaplan-Meier estimator was used to analyze five-year overall survival.

RESULTS

Gross total resection was achieved in 17 cases. Seven patients developed dehiscence of the pharyngeal wall, being the most common long-term complication. No instability was observed. Postoperatively, four patients received proton beam radiotherapy and 12 patients had combined photon and proton beam radiotherapy. The five-year overall survival rate was 72.6%.

CONCLUSION

With thorough preoperative planning, appropriate surgical techniques, and the addition of adjuvant radiotherapy, results similar to those in primary surgery can be achieved.

A Novel Reconstruction Using a Combined Anterior and Posterior Approach After Axis Tumor Spondylectomy

STUDY DESIGN

This was a retrospective study.

OBJECTIVE

To describe a novel reconstruction strategy using a T-shaped titanium mesh cage with posterior cervical screw-rod fixation after total spondylectomy of axis tumors.

SUMMARY OF BACKGROUND DATA

Instability of the upper cervical spine because of tumors in axis (C2) often results in devastating complications. Surgical resection and reconstruction after spondylectomy of C2 remain a technical challenge because of the intricate anatomies, vital adjacent tissues, and the unique spinal biomechanics in this special region.

MATERIALS AND METHODS

The novel reconstruction mode included the construction of the anterior aspect conducted with a specially made titanium mesh cage and the posterior cervical fixation only. Patients who received total C2 tumors spondylectomy and reconstruction with this novel mode in our center between January 2009 and December 2017 were retrospectively analyzed to evaluate the efficacy of this novel reconstruction method.

RESULTS

A total of 24 patients with C2 tumor received total spondylectomy and the new mode of local reconstruction. The neurological deficits recovered well and local pain relieved significantly (P<0.001) during the mean follow-up time of 22 months. Perioperative complications were rare and controllable. No internal fixation failure occurred. The mobility of the occipital-cervical junction was largely preserved in all patients.

CONCLUSIONS

This novel reconstruction mode using an anterior "T-shaped" mesh cage with posterior screw-rod fixation provides satisfactory stability and motion of occipital-cervical junction with limited complications, and therefore may prove to be an ideal option for management of C2 tumors.

LEVEL OF EVIDENCE

Level IV.

Management of C2 Body Giant Cell Tumor by Innovatively Fashioned Iliac Crest Graft and Modified Cervical Mesh Cage Used as Plate

BACKGROUND

Locally aggressive vertebral body tumors of the axis must be treated with wide local excision for best outcome. Reconstruction of the load-bearing vertebra needs to be done after tumor resection in such a manner so as to give stable, long-term fusion in this young population.

METHODS

We describe the management strategy of a 25-year-old acutely quadriplegic patient, with respiratory distress, with a C2 giant cell tumor. The use of a novel iliac crest graft modification used for C2 reconstruction along with a modified mesh cage used as an anterior plate has been reported.

RESULTS

The patient had a good outcome at 18 months' follow-up, with neurologic improvement and a solid fusion.

CONCLUSIONS

Iliac crest autograft is inexpensive and easy to harvest and can be considered as a C2 prosthesis, especially in a resource-constrained setting. Modified iliac crest graft can be used for load transmission from C1 lateral mass to C3 body, and the mesh cage can be modified according to need as a plate with good results in an emergency.

Reconstruction of the anterior craniocervical junction using an expandable cage after resection of a C1 chordoma in a 5-year-old child: case report

Chordomas are histologically benign tumors with local aggressive behavior. They arise from embryological remnants of the notochord at the clivus, mobile spine, and sacrum. Chordomas are rare tumors in the pediatric age group. Their surgical management is difficult, given their propensity for inaccessible anatomical regions, and proximity to critical neurovascular structures. While en bloc resection with surgical margins has been advocated as the preferred approach for chordomas, tumor characteristics and violation of adjacent anatomical boundaries may not allow for safe en bloc resection of the tumor. Here, the authors present the case of a C1 chordoma in a 5-year-old boy with epidural and prevertebral extension. The patient's treatment consisted of a far-lateral approach for resection of the tumor and C1 arch, followed by circumferential reconstruction of the craniocervical junction with an expandable cage spanning the skull base to C2, and posterior occipitocervical spinal instrumentation. At 42 months after surgery, the patient remains neurologically intact with stable oncological status, and no evidence of craniocervical junction instrumentation failure.

3-dimensional printing for anterior cervical surgery: a review

Age-related degenerative changes and non-spondylotic pathologies of the cervical spine such as trauma and tumor can lead to compression of neurological structures and result in substantial alteration of the structural anatomy. The end-goal of surgical intervention is to decompress the neural structures which can be achieved via an anterior or a posterior approach, and stabilization of segments to restore stability and alignment. Three-dimensional printing (3DP or Additive Manufacturing) has been applied to the field of medicine, in particular orthopedics and neurosurgery. Coupled with advances of medical imaging such as computed tomography (CT) scans and magnetic resonance imaging (MRI), accurate 3D models of patient anatomy can be produced, and patient-specific implants (PSIs) for complex anatomical reconstruction have all been applied with positive outcomes. 3D printed implants have been applied in particular to the cervical spine predominantly due to the complex and relatively small osteological anatomy and the proximity of important neurovascular structures to the surgical sites. The purpose of this review is to evaluate the current application of 3DP for cervical spinal implants. This includes a review on the available literature on 3D printed PSIs and current available 3D printed "off-the-shelf" (OTS) implants (3D-OTS). Suitable materials for 3DP of spinal implants and the future prospect of cervical implants will be discussed. The review will be concluded with a suggested guide for carrying future studies to evaluate the efficacy and safety of 3DP for cervical spinal implants.

Biomechanical evaluation of a novel integrated artificial axis: A finite element study

Various modified instruments are used for the anterior reconstruction of the tumor lesion affecting the second cervical vertebra, but there have been no reports regarding individual integrated artificial axis (IAA) prosthesis fabricated by selective laser melting. In the present work, a new type of IAA prosthesis has been designed with a 3-dimensional (3D) finite element model of normal occiput-the fourth cervical vertebra being established to assess its biomechanics. For easy comparison, another 3D finite element model is also established for the T-shaped Harms cage and an additional posterior fixation was performed on each model. The models are tested under a preliminary loading of 40 N to simulate cervical physical action including flexion, extension, lateral bending, and rotation. Under various loads from 4 different directions, the maximum stress and displacement of the IAA are less than those of the modified T-shaped Harms cage. Except for flexion, the maximum stress of the third cervical vertebra endplate of the IAA is smaller than that of the modified T-shaped Harms cage. The new prosthesis with axis is a good choice for upper cervical operation, which not only can greatly increase the operation stability of the upper cervical segment but also could significantly reduce the risk of fixation failure due to Harms cage subsidence.

Surgical treatment of upper cervical spine metastases: a retrospective study of 39 cases

BACKGROUND

The surgical treatment of upper cervical spine metastases are controversial up to now. By summarizing and analyzing the clinical data of the upper cervical spine involved metastases treated surgically in our center, we mainly aimed to investigate the surgical decisions and outcomes so as to provide more references for the clinical treatment of this special and complex spine metastasis.

METHODS

We evaluated the patients' pre- and post-operative neck pain and neurologic function with paired t test, followed by the statistics of the selection of surgical approaches, ways of reconstruction, and related complications. Moreover, the Kaplan-Meier survival analysis was adopted to analyze the patients' survival according to different growth group (rapid, moderate, and slow).

RESULTS

There were 39 patients with atlantoaxial metastases in this study. The most common symptom (94.87%) was occipital-cervical pain, which relieved greatly after surgical interventions (p < 0.01). The metastases mainly resulted from lung cancer and nasopharyngeal cancer with an incidence of 38.46 and 10.26%, respectively. As to different growth group, the rapid-growth tumors accounted for 69.23% in all atlantoaxial metastases. Tumor resection and stabilization were performed mainly via the combined anterior and posterior approach (66.67%). The 1-, 2-, and 3-year overall survival rate at the last follow-up was 58.5, 40, and 28.3%, respectively, with a median survival time of 18 months. The rate of complications associated with the surgical intervention was 12.82% (5/39), which is lower than that of the previous reports and generally controllable.

CONCLUSIONS

Relatively radical interventions with surgery for upper cervical spine metastases offered satisfactory outcomes with a low mortality. Together with adjuvant therapy, surgical treatment benefits patients with atlantoaxial metastases by relieving regional pain, restoring or improving the neurologic function, stabilizing the quality of life, and prolonging the survival time of such patients.

Anterior Spinal Reconstruction to the Clivus Using an Expandable Cage After C2 Chordoma Resection Via a Labiomandibular Glossotomy Approach: A Technical Report

INTRODUCTION

En bloc resection of high-cervical chordomas is a technically challenging procedure associated with significant morbidity. Two key components of this procedure include the approach and the method of spinal reconstruction. A limited number of reported cases of en bloc resection of high-cervical chordomas have been reported in the literature.

CASE PRESENTATION

We report a novel case using an expandable cage to reconstruct the anterior spinal column above C2 with fixation to the clivus. We also report a novel anterior approach to the high-cervical spine via a midline labiomandibular glossotomy. We detail the management of complications related to 2 instances of wound dehiscence and hardware exposure requiring two additional operations. The final surgical procedure involved explantation of the anterior cervical plate and use of a vascularized radial graft to close the posterior pharyngeal defect and protect the hardware. At 26-month follow-up, the patient remained disease free without any neurologic deficit.

DISCUSSION

We report the novel use of the midline labiomandibular glossotomy for surgical approach and reconstruction of the anterior column to the clivus with an expandable cage. The unique features of this operative strategy allowed the surgical team to tailor the construct intraoperatively, resulting in solid arthrodesis without significant neurologic sequelae.

CONCLUSIONS

Labiomandibular glossotomy for approach to high anterior cervical chordomas followed by craniospinal reconstruction to the clivus with an expandable cage represents a novel technique for managing high cervical chordomas.

Novel reconstruction of the anterior craniocervical junction using an expandable cage with integrated fixation after total C2 spondylectomy for chordoma

Chordoma is a locally aggressive malignant tumor that generally occurs in the clivus, mobile spine and sacrum. While en bloc resection with wide margins has been advocated as the only cure for chordomas, tumor characteristics and violation of critical anatomical boundaries may preclude pursuing this treatment option in the cervical spine. We present a C2 chordoma in a 35-year-old man with epidural and prevertebral extension that was treated with a single stage anterior-posterior total C2 spondylectomy with novel reconstruction using an expandable cage with integrated fixation followed by stereotactic radiosurgery. Single stage intralesional total C2 spondylectomy via anterior transoral and posterior approaches was performed. The anterior column was reconstructed using an expandable cage with integrated fixation from the clivus to C3. The patient maintained his intact neurological status at 6 month follow-up with full resumption of activities of daily living without any significant morbidity.

Fusion following lateral mass reconstruction in the cervical spine

OBJECT

Recently, aggressive surgical techniques and a push toward en bloc resections of certain tumors have resulted in a need for creative spinal column reconstruction. Iatrogenic instability following these resections requires a thoughtful approach to adequately transfer load-bearing forces from the skull and upper cervical spine to the subaxial spine.

METHODS

The authors present a series of 7 cases in which lateral mass reconstruction with a cage or fibular strut graft was used to provide load-bearing support, including 1 case of bilateral cage placement.

RESULTS

The authors discuss the surgical nuances of en bloc resection of high cervical tumors and explain their technique for lateral mass cage placement. Additionally, they provide their rationale for the use of these constructs throughout the craniocervical junction and subaxial spine.

CONCLUSIONS

Lateral mass reconstruction provides a potential alternative or adjuvant method of restoring the load-bearing capabilities of the cervical spine.

En bloc resection of a multilevel high-cervical chordoma involving C-2: new operative modalities

En bloc resection of cervical chordomas has led to longer survival rates but has resulted in significant morbidities from the procedure, especially when the tumor is multilevel and located in the high-cervical (C1–3) region. To date, there have been only 5 reported cases of multilevel en bloc resection of chordomas in the high-cervical spine. In this technical report the authors describe a sixth case. A complete spondylectomy was performed at C-2 and C-3 with spinal reconstruction and stabilization, using several new modalities that were not used in the previous cases. The use of 1) preoperative endovascular sacrificing of the vertebral artery, 2) CT image-guidance, 3) an ultrasonic aspirator for skeletonizing the vertebral artery, and 4) the custom design of an anterior cage all contributed to absence of intraoperative or long-term (20 months) hardware failure and pseudarthrosis.

Sequentially staged resection and 2-column reconstruction for C2 tumors through a combined anterior retropharyngeal-posterior approach: surgical technique and results in 11 patients

BACKGROUND

Surgical treatment of C2 tumors remains challenging. Because of the deep location and unique anatomical complexity, anterior exposure in this region is considered difficult and dangerous, and few reports concerning anterior tumor resection and reconstruction exist.

OBJECTIVE

To describe a technique of sequentially staged resection and 2-column reconstruction for C2 tumors through a combined anterior retropharyngeal-posterior approach.

METHODS

Eleven patients with C2 tumors underwent sequentially staged tumor resection and 2-column reconstruction in our institute. Eight primary lesions and 3 metastases were involved. Tumor resections and anterior reconstructions with conventional constructs were accomplished by an anterior retropharyngeal approach, and occipitocervical fusions through posterior access were performed in the same anesthesia.

RESULTS

No operative mortality occurred in this series. All patients experienced pain relief and neurological improvement after surgery. Except for 1 incidence of screw pullout, which was corrected by revision surgery, solid fusion was achieved in all patients. A follow-up period of 12 to 37 months was available for this study. Two patients with chordoma relapsed; 1 died of disease, and the other was alive with disease. Two patients with metastasis died of multiple remote metastases. No evidence of local recurrence was found in the other patients.

CONCLUSION

The anterior retropharyngeal approach is a favorable route to treat tumor lesions of the C2 vertebral body that allows tumor resection and placement of anterior constructs between C1 and the subaxial vertebral body. Tumor resection and 2-column reconstruction could safely be accomplished simultaneously through the combined anterior retropharyngeal-posterior approach.

Partial spondylectomy for primary leiomyosarcoma of C2 vertebra

STUDY DESIGN

A primary leiomyosarcoma located on the left side of the C2 is reported. Left-sided partial spondylectomy and anterior reconstruction with posterior stabilization was performed by a two-staged operation.

OBJECTIVE

To emphasize the occurrence of primary leiomyosarcoma and the importance of proper stabilization in the upper cervical spine.

SUMMARY OF BACKGROUND DATA

Leiomyosarcoma is a rare malignant neoplasm of the bone and the primary leiomyosarcoma of the spine is extremely rare. Radical tumor excision is the goal in case of vertebral leiomyosarcoma, but to both gain surgical access to the upper cervical spine and obtain anterior reconstruction is challenging.

METHODS

Leiomyosarcoma of the C2 in a 25-year-old woman with mild neurologic deficits is reported. A left-sided partial spondylectomy of C2 was performed. The defect of the vertebral body was reconstructed by expandable titanium prosthesis, and posterior craniocervical fixation was performed by the polyaxial screws in the lateral masses and rod/plates.

RESULTS

The surgical margin was very small. The pathology of the tumor was reported as leiomyosarcoma. No sign of local recurrence or metastasis was evident 1 year after surgery.

CONCLUSION

Leiomyosarcoma, although rare, should be kept in mind as one of the possible diagnoses when a patient with an upper cervical tumor is presented and complete tumor removal must be the goal.

Intraarticular atlantooccipital fusion for the treatment of traumatic occipitocervical dislocation in a child: a new technique for selective stabilization with nine years follow-up

STUDY DESIGN

A case report of traumatic atlantooccipital dislocation (AOD) managed by intraarticular-posterior fusion from a posterior approach at the C0-C1 level with preservation of C1-C2 motion.

OBJECTIVE

To present a new technique for atlantooccipital fusion with long-term follow-up.

SUMMARY OF BACKGROUND DATA

There is an increasing number of patients with AOD who have preservation of neurologic function. The most frequent method used to treat this condition is occipitocervical fusion. There has been a tendency in recent years to minimize the extent of stabilization, performing occipitoatlantal fusion only. However, it is difficult to achieve a solid fusion between C0 and C1, and the long-term effect of the insufficiency of lig. alaria on C0-C2 stability is unknown. The authors present a modified technique of C0-C1 fusion that aims to enhance fusion and achieve greater stability.

METHODS

A 11-year-old child with AOD was initially treated unsuccessfully with a halo device for 3 months. As instability persisted, an isolated C0-C1 fusion was performed from a posterior approach. This anatomically based intraarticular fusion technique comprises removal of the articular cartilage of the atlantooccipital joints, and cancellous bone autografting at the atlantooccipital joints and between the occiput and posterior arch of C1, supported by an occipital plate linked by rods to lateral mass screws in the atlas.

RESULTS

This technique of increased bony fusion surface and internal fixation provided an excellent result with full recovery of minor neurologic deficits. At long-term follow-up, 9 years after surgery, the patient was free of signs and symptoms; solid fusion of the C0-C1 joint, and normal values for rotation of the C1-C2 segment were recorded.

CONCLUSION

Intraarticular and posterior fusion of the atlantooccipital joint was able to provide an excellent long-term clinical outcome in the treatment of traumatic AOD in a child. This is the first report of an intraarticular fusion of the C0-C1 segment and the longest follow-up published on isolated C0-C1 stabilization.

[Transoral vertebroplasty: an alternative for operative treatment of metastases of the upper cervical spine]

Analogue to the demographic changes and the accompanying increased incidence of tumorous diseases, the number of patients with metastatic bone tumors of the spine is also increasing. Metastatic bone tumors are the most significant cause of pain in cancer patients. Pain and instability are the main indications for surgery. Minimally invasive procedures are recommended in patients with a poor medical condition and with a poor prognosis.Transoral vertebroplasty can be successfully used to reduce pain and provide stability in the palliative treatment of metastases of the vertebral axis. This procedure has the advantage of providing rapid pain relief and spinal stabilization.The operative technique is described and discussed with reference to the current literature. As an example the case of a 67-year-old patient is described, who was suffering from prostate cancer and a painful metastasis of the dens axis. After interdisciplinary consensus, transoral vertebroplasty was performed. The procedure was effective in achieving pain relief and providing stability and 7 months after the operation no further spinal metastases had occurred.

Biomechanics and materials of reconstruction after tumor resection in the spinal column

We initially review the general biomechanical principles that should be considered in surgical reconstruction of spinal tumors. This will be further clarified by more detailed descriptions for individual spinal regions in the subsequent part of the article. In the case of patients with spinal metastases, especially in patients with a median survival time less than a few months, a thorough review of the risks and benefits regarding surgical intervention must be discussed with the patient. However, once the decision for surgery has been made, a biomechanically sound reconstruction should be performed to help restore or maintain the patient's mobility.